PPC: skip all Simd tests on PPC

As of https://crrev.com/c/2629465, Simd tests cannot pass on
architectures without Simd support. Tests will need to be re-enabled
once Simd support is fully implemented on PPC.

Change-Id: I963639f1afa0c0ca7be3ca4b2fc06e874235b903
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2693056


Reviewed-by: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72788}